{smcl}
{* 2feb2012}{...}
{hline}
help for {hi:sgmediation}
{hline}

{title:Sobel-Goodman mediation tests}

{p 8 16 2}{cmd:sgmediation}
  {it:depvar} [{cmd:if} {it:exp}] [{cmd:in} {it:range}]
  {cmd:,}
  {cmd:mv:(}{it:mediatorvar}{cmd:)}
  {cmd:iv(}{it:indvar}{cmd:)}
    [ {cmd:cv(}{it:covarlist}{cmd:)} {cmd:quietly} ]

{title:Description}

{p 4 4 2}
The purpose of the Sobel-Goodman tests are
to test whether a mediator carries the influence of an IV to a DV.

{p 4 4 2}
 A variable may be considered a mediator to the extent to which it carries the influence of 
 a given independent variable (IV) to a given dependent variable (DV). Generally speaking, 
 mediation can be said to occur when (1) the IV significantly affects the mediator, (2) the 
 IV significantly affects the DV in the absence of the mediator, (3) the mediator has a 
 significant unique effect on the DV, and (4) the effect of the IV on the DV shrinks upon 
 the addition of the mediator to the model.
 
{title:Options}
{p 4 8 2}{cmd:cv(}{it:covarlist}{cmd:)} Optional list of covariate variables.{p_end}
{p 4 8 2}{cmd:quietly} Suppresses the individual regression output.{p_end}

{title:Examples}

{p 4 8 2}{cmd:. sgmediation science, mv(read) iv(math)}{p_end}
{p 4 8 2}{cmd:. sgmediation science, mv(read) iv(math) cv(write)}{p_end}

{p 4 8 2}{cmd:* bootstrap with case resampling}{p_end}
{p 4 8 2}{cmd:. bootstrap r(ind_eff) r(dir_eff), reps(1000): sgmediation science, mv(read) iv(math)}{p_end}
{p 4 8 2}{cmd:. estat bootstrap, percentile bc}{p_end}

{p 4 8 2}{cmd:* bootstrap with residual resampling}{p_end}
{p 4 8 2}{cmd:* need to install resboot_mediation}{p_end}
{p 4 8 2}{cmd:. findit resboot_mediaton}{p_end}
{p 4 8 2}{cmd:. resboot_mediation, dv(science) mv(read) iv(math) reps(1000)}{p_end}

{title:Author}

{p 4 4 2}Phil Ender{break}UCLA Statistical Consulting Group
{break}ender@ucla.edu

{title:References}

{p 4 8 2}Aroian, L. A. (1944). The probability function of the product of two normally distributed variables. 
{it: Annals of Mathematical Statistics}, {it: 18}, 265-271.{p_end}
{p 4 8 2}MacKinnon, D. P., & Dwyer, J. H. (1993). Estimating mediated effects in prevention studies. 
{it: Evaluation Review}, {it: 17}, 144-158.{p_end}
{p 4 8 2}MacKinnon, D. P., Warsi, G., & Dwyer, J. H. (1995). A simulation study of mediated effect 
measures. {it:Multivariate Behavioral Research}, {it:30}(1), 41-62.{p_end}
{p 4 8 2}Preacher, K. J., & Hayes, A. F. (2004).  SPSS and SAS procedures for estimating indirect effects in simple 
mediation models. {it:Behavior Research Methods, Instruments, & Computers}, {it:36}(4), 717-731.{p_end}
